(1) Field of the Invention
The invention relates to an apparatus and method for cutting and harvesting infestations of bottom growing aquatic vegetation and/or skimming algae/floating vegetation in shallow areas of water bodies.
(2) Description of the Related Art
Bottom growing nuisance aquatic plants and floating algae/floating vegetation and degradation of waters for swimming, boating, fishing, aesthetic and health aspects by lake users and waterfront property owners. Currently these plants can be removed by physical, mechanical, chemical and biological methods each with significant drawbacks.
Physical methods, such as barriers disturb water-bottom ecology and often result in gassing of decomposing plant like vegetation under the barrier. Examples of such mat material are filtration mats, discarded rugs and thin sheets of metal plate.
Mechanical bottom cutting and drag devices such as commonly used rake like tools and typical garden type cultivators that have transverse bars, tines and handles stir up bottom sediments which release nutrients back into the waters and disturb water bottom ecology. These nutrients enhance further aquatic plant growth and digging up the bottom sediments can have a negative impact on the lake bottom ecology.
The following patents are examples of bottom, metal, drag-type cutters which dig up bottom sediment as well as not integrally harvesting the floating cut aquatic plants. These floating plants can then reestablish themselves in other areas of the water body. A further disadvantage of these water bottom drag-type cutters is that they are prone to be blocked or other wise interfered with during digging by rocks, logs and debris that have accumulated on the lake bottom. U.S. Pat. No. 6,250,054 Kramer; U.S. Pat. No. 2,065,733 Pearson; U.S. Pat. No. 2,702,975 Friesen; U.S. Pat. No. 2,790,297 Gardner; U.S. Pat. No. 3,601,956 Akermanis; U.S. Pat. No. 3,601,956; U.S. Pat. No. 4,137,693 Thompson et al; U.S. Pat. No. 4,375,299 Laven; U.S. Pat. No. 3,863,237 Doer; U.S. Pat. No. 4,696,149 Hawk; U.S. Pat. No. 4,852,337 Peterson; U.S. Pat. No. 5,189,867 Schmidt; and U.S. Pat. No. 5,493,850 Torkelson; each show methods for cutting plants using a drag bar with a cutting edge. U.S. Pat. No. 4,999,982 Kriger describes the use of a dragging bar grate for cutting aquatic plants. U.S. Pat. No. 4,583,353 Shaver shows a triangular drag bar for cutting plants.
Chemical and biological methods are under investigation. However, there is concern about these methods, because of questions of effectiveness, damage to water ecology, known and unknown water-related human health impacts and possible liability considerations for the user.
Another type of plant cutting involves the commercial mechanical lake weed harvesters having reciprocating knives and conveyors. These machines with on-board power are heavy, complicated, costly and hazardous. Further, these machines are often unworkable in shallow areas of lakes and other bodies of water, because of hydraulic boat draft problems resulting in grounding of the harvester and engine cooling water problems from intake of lake bottom sediments into the engine. Examples of commercial powered and mechanized lake weed harvesters are U.S. Pat. No. 4,616,588 Caddick; U.S. Pat. No. 3,238,708 Zickeford; and U.S. Pat. No. 5,404,696 Vasby. These harvesting units are expensive, require considerable maintenance, need US Coast Guard permits in US navigable waters and require marine Workman's Compensation insurance under the Jones Act.
There are also wheeled garden rakes that are used on dry land. Codding U.S. Pat. No. 4,945,996 and Foeller U.S. Pat. No. 5,287,935 are examples of such dry land garden rakes, which disturb lake bottom ecology.